AE2023: Parent object to null-parented path with round corners?

Question

So this is a bit of an odd usage scenario even for AfterEffects, but I wanted to see if it might be possible. Short version, I have a path that I made with the Pen tool, whose anchor points are parents to nulls, with a Round Corners effect applied.

Is there a way to get another object to animate along a path set up like this?

The only way I know of to get an object to animate along a path is to copy the path itself and paste it onto the Position property of the object I want to animate. That isn't working with this setup, and neither is trying to drag the parent pickwhip from the object's Position property to the Path property of the path layer.

Failing that, I'm out of ideas. Is what I'm describing even possible?

Answer 1

This isn't easily modifiable but should work:

Make the shape path

Round the corners

Make the stroke width as thin as possible but visible

Select Layer --> AutoTrace, and AutoTrace the shape, being sure to set all the tolerances very low, so the traced version closely fits your original rounded path.

After tracing, you will have a new layer containing some masks. Make sure there's only one mask - find the right one that best matches your shape. Delete any extra ones that appear that are not needed.

Copy the mask keyframe.

Select the new object that you want to move along the path. Give it one position keyframe.

Paste your mask keyframes onto the position keyframe of your second object.